1. Field of the Invention
The present invention relates generally to key origination and duplication and, more particularly, to the field of forming a key from a key blank even when the original or pattern key to be duplicated is lost or otherwise unavailable.
2. Discussion of the Background Art
The need to fabricate duplicate keys undoubtedly dates back to the earliest implementation of the lock, the earliest methods of making duplicate keys being the exclusive province of skilled artisans who used files and other hand tools to slowly shape a small section of metal into the desired key form. The electric motor, of course, made it possible to mechanize the process of forming and shaping duplicate keys, and a key of moderate complexity can typically be duplicated-by a relatively unskilled worker in a matter of minutes. Since its introduction and subsequent widespread commercial acceptance, however, the mechanized key duplication process has changed very little over the years.
Conventional key duplication systems operate on one of three general principles. Systems of the first type utilize a tracing principle wherein a specimen key with the essential pattern profile (i.e., a “pattern” key) is placed into a first vise clamp. A key blank to be contoured with the essential pattern is placed into a juxtaposed second vise clamp. The pattern key is brought into contact with a guiding stylus, while the key blank is brought into contact with a cutting wheel. A carriage associated with the vise clamps is then shifted laterally and angularly reoriented inwardly and outwardly, such that the engagement of the pattern key with the stylus imparts a corresponding pivotal movement of the carriage and the cutting wheel removes material from the working edge surface of the key blank to form a contoured profile matching that of the pattern key. When this process has concluded, the key blank is removed from the vise clamps, and any burrs or other imperfections formed during the cutting operation are removed with a file or a buffing wheel. Early machine configurations of the pattern key tracing type are exemplified by U.S. Pat. No. 1,752,668 entitled “Key Duplicator” issued to Johnson on Apr. 1, 1930. More recently, the inventors herein disclosed, in U.S. Pat. No. 7,530,884 entitled “System and Method for Duplicating Keys”, an improved key duplicating machine which utilizes a profiled cutter having an abrasive surface. This abrasive cutter is driven at a much higher rate of speed (e.g., 30,000 rpm) than the slower turning, toothed cutting wheels that had previously characterized the prior art. This configuration resolved a number of deficiencies in the prior art, including the tendency of the key blank to shift or jump out of the clamping vice under the action of the slow rotating cutting teeth.
In conventional key duplication systems of the second type, height wise adjustment and spacing of the cuts along the working edge of the key blank are effected by indexing means which position the cutter and key blank in accordance with a code, so that if the code of the specimen key to be duplicated is known, the key may be duplicated without the actual presence of the pattern key. Apparatus configurations of the code key cutting type are exemplified by U.S. Pat. No. 1,750,218 entitled “Key Cutting Machine” and issued to Falk on Mar. 11, 1930, U.S. Pat. No. 1,811,922 by the same title and issued to Falk (on Jun. 30, 1911), and U.S. Pat. No. 3,469,498 entitled “Code Key Cutter Device” issued to Adler et al on Sep. 30, 1969. The Falk machines used sets of detachable and removable discs to regulate the spacing and depth of the notches to be cut along the working edge of the key blank. Each disc had a series of holes that were numbered to match the lock manufacturer's specifications. Space and depth keys were provided to set the spacing and depth of cut prior to originating keys. Over the years, more than 150 sets of discs were made for a now-discontinued machine known as the Universal Code Machine. More recently, computer controlled cutting machines that use complex electronic control systems, an onboard database of codes specifying notch spacing and depth have been introduced. Examples of this more recent type include the one disclosed in U.S. Pat. No. 5,711,643 issued on Jan. 27, 1998 to Parr et al.
A third type of key duplication system, a variation of the code key cutting type, utilizes a “key nipping tool” to remove material from along the working edge of the key blank. The user is guided by an index card that has predetermined code depth and spacing information. A system of this type is disclosed in U.S. Pat. No. 5,054,350 entitled “Key Punch Machine” and issued to Gartner et al. on Oct. 8, 1991.
One of the benefits of the abrasive-cutter based system disclosed in U.S. Pat. No. 7,530,884 is that it is easy and economical to manufacture, maintain and operate. The '884 system, sold by Roto-Smith Tools LLC of North Brunswick, N.J., is not limited to duplication of pattern keys. It has also been used for reproducing a key of which only the code number is known. In this case, individual depth-and-spacing or “matrix” keys have been used, one at a time, in place of the original key to be traced. Each matrix key comprises notches spaced apart from one another by a distance equal to the spacing between the notches of the key to be produced, all these notches having the same depth in a given matrix key and one matrix key existing for each figure of the code, i.e. for each possible depth for a notch. A first matrix key corresponding to the first figure of the code is fixed in front of the stylus and the stylus is engaged in the first notch of the matrix key so as to cut the first notch in the blank. The first matrix key is then replaced by a second matrix key corresponding to the second figure of the code and the stylus is engaged in the second notch of the second matrix key so as to cut a second notch in the blank. This operation is continued successively for all the figures of the code.
The aforementioned process of using the '884 system is far from optimal. After each notch has been cut, the next matrix key must be repositioned in the clamping vise to account for the next notch depth. This repositioning process is time consuming, complicated and a potential source of error. Furthermore, a determined notch of the matrix, and only this notch, must be scanned by the stylus. This operation is delicate; if the carriage slips relative to the stylus, the cutter forms a notch of incorrect shape and the blank being cut must be scrapped. This latter drawback may be overcome by providing one matrix per depth and per possible location of notch, but, in that case, the number of matrices is considerably increased. Great skill and precision on the part of the operator is demanded.
A continuing need therefore exists for a code key machining system which is simple and economical to manufacture, easy to operate and maintain, and which does not introduce so much error into the process that the keys produced will not perform their intended function.
A further need exists for a key machining system which can be optionally adapted to make use of an original key when the same is available.